I have to tell you, if you are spraying this primer and flat black out of a rattle can, it will not protect much, if at all. A 2K primer like epoxy or urethane will protect from moisture "to a point". It is not designed to do that job, paint is. It will however protect for some time against rain or washing with no ill effects. But it is not designed to protect for extended periods of time.
The 1K primer from a rattle can, it will do almost NOTHING. Even one washing will likely cause damage.
